Answer:
The error is that you're trying to convert a string with letters inside into an int. What happens if a user type in 'a' instead of '1'? 'a' is not a number so the int('a') would fail and give you an error. Make you add a line to check whether the input a number or not.
Explanation:
Change your code to
DEorAP = input("Is it AP or DE?")
if DEorAP.isdigit()
DEorAP = int(DEorAP)
